Cutting insert and associated milling cutter

ABSTRACT

The invention relates to a cutting insert used for cutting metal, especially for milling for example camshafts. The inventive insert comprises at least one cutting edge ( 4, 4 ′) that is formed by the intersection of a face ( 2 ) with a flank ( 3 ). The aim of the invention is to provide a cutting insert for a milling cutter and a corresponding milling cutter the noise level of which, even if at full load, is considerably reduced for high-speed milling. To this end, the cutting edges ( 4, 4 ′) extend at an angle deviating from 90° relative to the cutting direction of the cutting insert.

[0001] The present invention concerns a cutting insert for cutting metalmachining, in particular for milling for example camshafts, comprisingat least one cutting edge formed by the intersection of a rake face witha flank. The present invention also concerns a milling cutter for thecutting machining of a metal workpiece, wherein the milling cuttercomprises a tool body which is substantially cylindrical or in the formof a circular disk having a plurality of receiving pockets for cuttinginserts which are distributed along the periphery of the tool body.

[0002] Corresponding cutting bits or inserts and a corresponding millingtool are known for example from U.S. Pat. No. 4,867,616. In the knownmilling cutter the cutting inserts are approximately of a square basicshape with interrupted cutting edges which are bevelled in the cornerregions. The individual plates are distributed in alternate axiallyslightly displaced relationship along the periphery of a tool body whichis cylindrical or in the form of a disk, so that overall two differentgroups of cutting inserts are arranged in such a way that the one groupof cutting inserts projects in the one axial direction and the othergroup of cutting inserts projects in the other axial direction, beyondthe thickness of the disk-shaped tool body. All cutting inserts alsoproject slightly in the radial direction beyond the radius of the maintool body and they are received in corresponding recesses or receivingpockets in the main body of the tool. In that arrangement the activecutting edges are not oriented exactly parallel to the axis of the toolbody but are slightly inclined relative to the axis, that is to say theyare slightly tilted in a plane which is defined by the associated radiusvector and the axis of the tool body.

[0003] The displacement of the two cutting insert groups relative toeach other provides that the cutting edge portions of the one group ofcutting inserts cut substantially in the gaps of interruptions formed bythe interrupted cutting edges of the other group of cutting inserts.That provides that, even when both groups of cutting inserts overlap toa relatively great extent in the axial direction, the cutting insertsare nonetheless substantially uniformly loaded along their entire (evenif interrupted) cutting edges.

[0004] The cutting inserts can be turned and have up to eight(interrupted) cutting edges. Corresponding milling cutters can be usedto cut for example slots or grooves in workpieces. A correspondingmilling cutter is only limitedly suitable for the production ofcamshafts and at any event would require a plurality of successiveworking operations in order to produce the correct cam profile.

[0005] In the recent past the quality of the cutting inserts or thematerial from which they are produced has increasingly improved so thataccordingly it has also become possible to use further increasingmachining speeds without the risk of the cutting inserts being damagedor suffering from excessively rapid wear. It will be noted however thatthese higher machining speeds also entail the disadvantage of anincreased production of noise. In the case of almost all milling cuttersand almost all milling operations, the cutting edges or at least a partof the cutting edges are or is not permanently in engagement with theworkpiece which is in the course of being machined, but on the contrarythe cutting edges come into engagement and out of engagement again withthe workpiece intermittently, the engagement position extending onlyover a given angular region of the corresponding rotating milling tool.After a rotary movement through a given angle, depending on the natureof the machining operation and the depth of engagement, the previouslyactive cutting edges of a cutting bit initially come out of engagementwith the workpiece until, after a rotary movement through a furtherangle which in total generally affords an angle of 360° with thefirst-mentioned angle, they come into engagement with the workpieceagain, and the corresponding process begins afresh. That applies inregard to each individual cutting insert arranged along the periphery ofa corresponding milling cutter, in which case during a workpiecemachining operation a respective part of the cutting inserts which aredistributed over the periphery are in engagement with the workpiecewhile another part is just out of engagement therewith.

[0006] Engagement of an active cutting edge with the workpiece isgenerally effected abruptly after a corresponding rotary movement of thetool body, insofar as the respectively active cutting edge which issubstantially parallel to the axis comes into engagement over its entirelength simultaneously with the workpiece and a chip or a plurality ofchips are detached from the workpiece material during the further rotarymovement in the workpiece material. The moment of coming intoengagement, by virtue of the cutting edges striking against theworkpiece or the surface to be machined, causes a noticeably audiblenoise and the large number of cutting edges of the individual cuttinginserts, which come into engagement with the workpiece surface in rapidsuccession during a rotation of a milling cutter, produce a considerableamount of noise in the case of a milling cutter which is rotating fast.

[0007] In that respect industrial health and safety requirements providethat a noise level of 80 decibels is not to be exceeded by correspondingtools, in which respect the noise level is measured at precisely defineddistances relative to the workpiece and the milling cutter. With anincreasing machining speed, that is to say with an increasing speed ofrotation of the tool bodies or with an increase in the diameter of therotating tool bodies, the noise level produced further increases. Inaddition the relevant authorities in Europe are endeavouring to furtherreduce the maximum allowable noise level of 80 decibels to 75 decibels.This means that the machining speed and therewith also the productivityof corresponding machines would have to be reduced below the value whichwould otherwise be technically possible.

[0008] In comparison with that state of the art the object of thepresent invention is to provide a cutting insert for a milling cutterand a corresponding milling cutter, in the use of which, even whenmaking use of the full load capacity, it is possible to achieve aconsiderable reduction in the noise level in high-speed milling. It willbe appreciated that this is to apply, even when using cutting insertswith the highest available fracture strength and wear resistance, whichpurely technically permit maximum machining speeds.

[0009] In regard to the cutting insert itself the object of theinvention is attained in that the respectively active cutting edgeextends at an angle deviating from 90° relative to the cuttingdirection. This means in specific terms that, in the case of acorresponding, generally rotational movement of the cutting insert orthe cutting edge about the axis of a corresponding tool, the cuttingedge does not simultaneously come into engagement over its full lengthwith the workpiece, but firstly, by virtue of the inclination of thecutting edge with respect to the direction extending perpendicularly tothe cutting direction, a furthest leading portion of the cutting edge atan end thereof comes into engagement with the workpiece and it is onlyupon further rotary movement that the subsequent portions of the cuttingedge successively come into engagement with the workpiece. By virtue ofthe fact that the entire cutting edge does not abruptly come intoengagement with the workpiece the corresponding impact or chatter noiseis considerably damped, in which respect it will be noted that it mustbe presumed that the angle of inclination between the cutting edge and aline perpendicular to the cutting direction must exceed a certainminimum value as otherwise a unitary sound pulse is nonethelessproduced, which originates substantially from the entire cutting edge.An angle of between 40 and 85° of the cutting edge, relative to thecutting direction has proven to be appropriate, in particular between 50and 75°, while angles around 60°, that is to say in the range of between55 and 65° are particularly preferred.

[0010] A preferred embodiment of the invention is one in which theflanks or relief faces have structures which extend substantially in thecutting direction of the cutting insert, that is to say they adjoin thecutting edge at an angle which is markedly different from 90°. A furtherpreferred embodiment of the invention is one in which the cutting edgesare interrupted and each comprise at least two cutting edge portionswhich are separate but which extend substantially in the same directionand between which there is a gap or interruption. The flank or reliefface then has a correspondingly structured cross-section which remainsconstant as viewed in the cutting direction. For example it is possibleto provide at the ends of the cutting edges, cutting corners or chamferswhich are adjoined by corresponding chamfers or edges respectively onthe flanks.

[0011] The internal spacing between the individual cutting edge portionsof a cutting insert, which respectively belong together to the samecutting edge, in the preferred embodiment of the invention is to besomewhat smaller than the length of the individual cutting edge portionsthemselves. In that way it is possible for various cutting inserts to bearranged in suitably displaced successive relationship so that, in thegap region which the cutting edges of the preceding cutting insert leavebehind, a cutting edge of the next following cutting insert performs itscutting action, while the preceding cutting edges remove materialpredominantly in the region in which the respective successive cuttinginsert has a gap or interruption in its cutting edge. Desirably, thewidth or length of those cutting edge interruptions is of the order ofmagnitude of between 70 and 90%, preferably around 80% of the length ofthe individual cutting edge portions.

[0012] As already mentioned the ends of the active cutting edges of thecutting inserts should be angled, preferably at about 45°. At the outerends of the cutting insert those angled ends form a transition tosecondary cutting edges which extend substantially perpendicularly tothe main cutting edges but are markedly shorter and extend substantiallyover the thickness of the cutting insert.

[0013] The above-specified definitions and structures, in particular thefact that the flanks or relief faces have structures and for exampleedges which extend in the cutting direction, whereas the cuttingdirection in turn does not extend perpendicularly to the cutting edge,also entail inter alia the feature that the cutting insert according tothe invention, in plan view on to the flank or relief face, is in theform of a parallelogram (which is not right-angled). Rhombic cuttinginserts are admittedly known in principle in the state of the art, butin the case of those known cutting inserts the rhombic shape orparallelogram shape is not in a plan view on to a flank but rather in aplan view on to a rake face or the oppositely disposed support face.

[0014] Preferably the cutting inserts in accordance with the presentinvention each have a plurality of independent cutting edges so thatthey can be turned when one of the cutting edges is worn. Thus, aparticularly preferred embodiment of the invention is one in whichcutting edges are provided at different rake faces arranged on sides ofthe cutting insert, which face away from each other. It is also possibleto arrange on the same side, that is to say in principle adjoining thesame rake face, two respective cutting edges which are respectivelyformed by the intersection of a rake face with one of the two flanks orrelief faces which are on opposite sides. By a combination of thosefeatures, it is possible to produce cutting inserts with for examplefour cutting edges, in which respect the term ‘cutting edge’ is alwaysused to denote the portion which is active overall in a cuttingprocedure, even if it comprises a plurality of cutting edge portionswhich are separated by interruptions.

[0015] In a particularly preferred embodiment of the invention thecutting edge or the cutting edge portions belonging to a cutting edgeextend in a curved configuration, or the various cutting edge portionsextend at a small angle to each other, like closely adjacent tangents toa corresponding circle. Such a circular arc, along which the cuttingedges extend, should involve a radius of curvature of the order ofmagnitude of between 100 and 1000 mm. Instead of a curvedly extendingcutting edge which is relatively difficult to produce however it is alsopossible for example for adjacent cutting edge portions each to extendstraight in itself, while however being inclined relative to each otherat a small angle which is typically between 1° and 10°, preferably beingabout 5°. In more general terms, it can be said in respect of curvedcutting edges that the ends of a cutting edge, which are respectivelyremote from each other, (that is to say for example the tangents to theend portions), should include with each other a corresponding angle ofbetween 1° and 10°.

[0016] In regard to the milling cutter for the cutting machining of aworkpiece the object of the invention is attained in that at least apart of the receiving pockets of the tool body are of such anarrangement or configuration that the respectively active cutting edgeof the suitable cutting insert accommodated therein extends inclinedlyrelative to the axis of the tool body in the peripheral directionthereof. This means that the cutting edge is not inclined for example ina plane which is defined by the associated radius and the axis of thetool body, but in a plane perpendicular thereto, that is to say in aplane which is defined by a tangent to the tool body in the region ofthe cutting insert and a line parallel to the axis of the tool body.Admittedly this means that the radial spacing of parts of the cuttingedge relative to the axis of the tool body is inevitably also slightlyaltered, but that effect is comparatively slight if the cutting edgesare not excessively long and the angle of inclination does not exceed30°. In other respects however this effect can also be completelycompensated if, as already described above, the cutting edges of acutting insert are slightly angled relative to each other or, better,also extend along a circular arc whose precise radius is determined bythe radius of the tool body and by the inclination of the cutting edgerelative to the axis of the tool body.

[0017] As already mentioned the angle of inclination should be between 5and 45°, better between 10 and 40° and particularly preferably between25 and 35°, which means that the receiving pockets are adapted to thecutting inserts in such a way that the corresponding angle of the activecutting edges of at least a part of the cutting inserts is provided bythe receiving pockets on the tool body. In particular the active maincutting edges of the cutting inserts on the main tool body should be setin that way while the generally markedly shorter secondary cutting edgescan also retain an orientation substantially parallel to the axis of thetool body as they contribute comparatively little to the production ofnoise. In certain situations of use however it is also possible toenvisage a variant in which the secondary cutting edges are also tiltedrelative to the axis of the tool body in the described manner. In thatcase the secondary cutting edges of cutting inserts which are arrangedon opposite sides of a tool body can also be tilted in the oppositedirection. For reasons of space however the receiving pockets for thecutting inserts which are respectively active with their main cuttingedges are preferably provided in such a way that all cutting edges ofthose cutting inserts are inclined substantially in the same directionrelative to the axis of the tool body.

[0018] A particularly desirable configuration of the tool body is one inwhich a part of the inserts is arranged in the corner region between theoutside surface or periphery of the cylindrical tool body and the twoend faces of the tool body, while a further part of the cutting insertsis arranged only in the peripheral region of the cylindrical body.

[0019] In that respect a particularly preferred embodiment is one inwhich all four various groups of cutting inserts are provided on thetool body, which differ substantially by virtue of different axialpositions of the cutting inserts. In that respect a first group ofcutting inserts is arranged at the transition of an end face of thecylindrical tool body to the peripheral surface in such a way that thecutting inserts project substantially with their secondary cutting edgein a radial direction beyond the tool body. A further group of cuttinginserts is arranged in a quite similar manner but possibly displaced inthe peripheral direction at the transition of the other end face to theperipheral surface of the cylindrical tool body. The two remaininggroups of cutting inserts are arranged along the peripheral surface ofthe tool body and differ from each other by a slightly displaced axialposition, wherein the axial displacement is somewhat less than thelength of a cutting edge portion, wherein the cutting inserts haveinterrupted cutting edges, and the interruption between the cutting edgeportions is somewhat smaller than the length of one of the cutting edgeportions. In that way cutting edge portions of the one group cutprecisely in the region of the gap which is left behind by the cuttingedge portions of the other group, and vice-versa.

[0020] In addition, the ends of the active main cutting edges, which arerespectively axially closest to the end faces of the tool body, shouldoverlap with the secondary cutting edges of the cutting inserts arrangedin the corner region between the peripheral surface and the end face.Finally in that case the secondary cutting edges can also project in theradial direction somewhat further than the main cutting edges of thecutting inserts arranged on the peripheral surface. With such anarrangement, the cams of camshafts can be milled in a single workingoperation to the correct profile, that is to say with a profile of adisk, the edges of which are chamfered.

[0021] In a particular embodiment of the present invention, provided atat least a part of the seat surfaces of the main tool body of a millingcutter is a protruding projection which engages into a correspondingopening in a cutting insert received in the seat or the receiving meansof the main tool body. Desirably, such a projection is of such aconfiguration that it engages with as accurate a fit as possible intothe corresponding opening in the cutting insert, but bears at least withone of its peripheral surfaces against a boundary surface of the openingin order to secure the cutting insert to prevent lateral displacementthereof in at least one direction relative to the workpiece body. Bytightening a clamping screw or another clamping device, the cuttinginsert can then be pressed both against outer lateral seat surfaces andalso against at least one of the projection surfaces and that thereforeaffords a plurality of contact points which are spaced away from eachother and which fix the cutting insert in an accurate position on thetool body. At the same time it is possible in that respect to omit apart of the support surfaces which are otherwise to be provided forprecise positioning, along the outer periphery of the cutting insert,and that therefore provides more space on the tool body for a possiblymore compact arrangement of adjacent cutting inserts.

[0022] It will be appreciated that this configuration of a seat surfacewith a projection for fixing or positioning a cutting insert on a toolbody can also be used more generally and is not limited to use with theinclinedly set cutting edges in a milling cutter according to thepresent invention.

[0023] In the present case, in the illustrated embodiment, theprotruding projection is of a substantially trapezoidal cross-sectionwhich is substantially adapted to match the trapezoidal cross-section ofthe openings provided in the cutting inserts. It is also possible toprovide a plurality of short projection portions which engage at variouspositions into a correspondingly longer opening in a cutting insert.

[0024] Further advantages, features and possible uses of the presentinvention will be apparent from the description hereinafter of apreferred embodiment and the associated Figures in which:

[0025]FIG. 1 shows a perspective view of a diagrammatically illustratedembodiment of a cutting insert according to the invention,

[0026]FIG. 2 shows various views and variants of the cutting insertshown in FIG. 1,

[0027]FIG. 3 shows various variants of longitudinal sections throughcutting inserts as shown in FIGS. 1 and 2,

[0028]FIG. 4 shows various views of portions of a milling cutter withcutting inserts arranged thereon and the cutting profile producedthereby,

[0029]FIG. 5 shows the arrangement and fixing of the cutting insertsaccording to the invention on a main tool body,

[0030]FIG. 6 shows a perspective view of a realistically reproducedfirst embodiment of a cutting insert according to the invention, and

[0031]FIG. 7 shows a perspective view of a realistically reproducedembodiment of a cutting insert according to the invention.

[0032] Referring to FIG. 1 shown therein is a cutting insert generallyidentified by reference 1 in the form of a parallelepiped, with twoparallel upper and lower faces forming main flanks or relief faces 3,two front and rear faces which define rake faces 2 and finally also tworight and left faces 3′ which form secondary flanks or relief faces inrelation to the secondary cutting edges 5. While the main cutting edges4, 4′ and the secondary cutting edges 5 extend substantially at a rightangle to each other, the outer edge structures 7 or also the secondaryflanks 3′ do not extend at a right angle to the main cutting edges 4. Onthe contrary, in a plan view on to the flanks 3, the cutting insert isdistorted substantially into the shape of a parallelogram, as can beclearly seen from FIGS. 2, 4 and 5. In that respect however FIG. 1 isonly a diagrammatic illustration which does not absolutely preciselyreproduce the actual proportions involved.

[0033] It will also be seen from FIG. 1 that the cutting insert hasinterrupted main cutting edges 4, 4′, wherein the length of theinterruption 6 is somewhat shorter than the length of the main cuttingedge portions 4, 4′ and wherein further main cutting edges 4, 4′ areprovided at the rake faces adjoining the rearward side (not visible) ofthe cutting insert and in addition also provided at the visible frontside are cutting edges both along the upper edge of the rake face 2 andalso along the lower edge of the rake face 2. Overall therefore thecutting insert shown in FIG. 1 has four main cutting edges which eachcomprise two cutting edge portions 4, 4′. The ends of the individualmain cutting edge portions 4, 4′ are respectively angled at about 45°and form a transition into secondary cutting edges 5 at the outer endsof the cutting insert. Adjoining the angle configurations of the maincutting edge portions 4, 4′ are corresponding chamfers 7 and 8respectively of the flanks 3. The chamfers 7 and 8 or the edges thereofand therewith the boundaries of the individual flank portions 3 extendparallel to the arrow A defining the cutting direction of the cuttinginsert 1. Also provided at the center of the cutting insert is a fixingbore 9 which is only diagrammatically indicated here and which moreovercan also extend into the main flanks 3 adjoining the cutting edgeportions 4, 4′.

[0034]FIG. 2 shows various views of the cutting insert illustrated inFIG. 1, in sub-FIGS. 2a, 2 d and 2 e. In this respect FIG. 2acorresponds to a vertical plan view on to the main flanks 3, the fixingbore 9 being shown here somewhat larger than in FIG. 1, that is to sayprojecting into the main flanks 3. FIG. 2d corresponds to a view on tothe cutting insert shown in FIG. 2a along the arrow B and FIG. 2efinally corresponds to a view on to the cutting insert shown in FIG. 2ain the direction, of or opposite to the direction of the arrow A whichagain indicates the cutting direction. It will be seen that in thatcutting direction the cutting insert 4 roughly approximates to theprofile of a digit 8.

[0035]FIGS. 2b and 2 c show slightly modified variants of the cuttinginsert which can be seen in FIG. 2a, insofar as in FIG. 2b the two maincutting edge portions 4, 4′ are inclined relative to each other and arethus inclined relative to a symmetrically arranged front portion of theinterruption 6 through an angle of plus or minus β which is of the orderof magnitude of between 1 and 5°. As a result the two cutting edgeportions include an angle to each other of a maximum of 10°. In FIG. 2c,instead of the angle configuration of the two cutting edge portions 4,4′, the arrangement has a uniform curvature in respect of the cuttingedge configuration 4, 4′, wherein the radius of curvature shouldtypically be of an order of magnitude of between 100 and 1000 mm so thatthe two mutually remote ends of the cutting edge portions 4, 4′ havetangents which include with each other an angle of a maximum of 10°,preferably of the order of magnitude of between 1 and 5°. In thatrespect the radius of curvature to be adopted depends on the diameter atwhich the cutting insert in question is arranged on the milling cutter,measured from the axis thereof, and the angle of inclination of thecutting edge relative to the cutting direction, or the angle ofinclination, which is complementary thereto, with respect to the axis ofthe milling cutter. Ideally the radius of curvature should be soselected that the cutting edge portions 4, 4′ over their entire lengthare at a constant radial spacing from the axis of the milling cutter,that is to say they are disposed on a notional cylindrical surface aboutthe axis of the tool body, so as to provide a correspondingly constantcutting depth when milling. For rough machining however it is equallywell possible to use the insert shown in FIG. 2a, in which respect useof the insert shown in FIG. 2b forms an intermediate stage in machiningaccuracy.

[0036]FIG. 3 shows various sectional and side views of the cuttinginserts illustrated in FIG. 2, in particular in FIG. 2a, viewingupwardly, that is to say perpendicularly to the arrow B in FIG. 2. Inthat respect FIG. 3a corresponds to the shape of the cutting insertshown in FIG. 1, in which the rake faces 2 extend perpendicularly to theflanks or relief faces, so that there is a negative rake angle at leastin the milling procedure. The other cross-sectional shapes shown inFIGS. 3b through d permit operation with a positive rake angle. For thatpurpose, in the embodiment of FIG. 3b, adjoining the main cutting edges4, 4′ there are depressions in the rake face 2, while in the embodimentsof FIGS. 3c and 3 d the angle between the rake face and the flank orrelief face has been reduced, whereby the number of available maincutting edges has also been reduced as in both cases instead of fourcutting edges there are only two (positive cutting edges) available. Inthat respect the embodiment of FIG. 3c is also to be preferred insofaras, after the cutting insert has been turned, it involves the sameorientation for the diagonally oppositely disposed cutting edge, whilein the case of the embodiment of FIG. 3c, there is a respectivemirror-image orientation of the cutting edge configuration, indiagonally opposite relationship. In other words, the inclination of thecutting edge relative to the axis of a milling cutter changes in signwhen turning the cutting insert from one cutting edge to the other. Thathowever is also the case with the diagonally opposite main cutting edges4, 4′ of the cutting inserts with a total of four main cutting edges.For the use of such cutting inserts it is therefore desirable if twodifferent types of milling cutters are used, which is revised only bythe direction of the inclination of the receiving pockets or the cuttinginserts received therein, along the periphery of the milling cutter.That is also desirable in particular in relation to camshaft millingcutters because, in the case of camshaft milling cutters, a plurality ofcorresponding disk milling cutters generally come into engagement in anycase simultaneously with a camshaft, so that those disk milling cuttersshould respectively have in pairs a milling cutter of one type and amilling cutter of the other type, in order to be able to make optimumuse of the cutting inserts by exchanging them when changing the maincutting edges between the two milling cutters, if a main cutting edgewith the correct symmetry for the previous milling cutter is no longeravailable.

[0037] That will be better understood from the description relating toFIGS. 4 and 5 which show a portion of a milling cutter and thearrangement of the cutting inserts on such a milling cutter.

[0038]FIG. 4a shows a peripheral portion of a tool body 10 which issubstantially in the form of a circular disk and which has receivingpockets 11′ for cutting inserts 1 which are arranged along the cornerregion between an end face and the peripheral surface of the tool body10. FIG. 4b shows a plan view of the peripheral surface. It will be seenin this respect that in both corner regions at the transition of the endfaces to the peripheral surface of the milling cutter 10, receivingpockets 11 and 11′ respectively are arranged alternately, with arespective cutting insert 1 being received in each of the pockets.Provided also along the peripheral surface are receiving pockets 12 and12′ respectively which each define a seat for the cutting plates 1,wherein the receiving pockets 12 and 12′, alternate in the peripheraldirection and differ only by virtue of their axial position. The cuttinginserts 1 in the receiving pockets 12 are displaced somewhat towards theleft with respect to the cutting inserts 1 in the receiving pockets 12′,more specifically in such a way that the interruptions between thecutting edges of the one group of cutting inserts are respectivelycovered by cutting edges of the other group of cutting inserts. Inaddition the cutting edges of the cutting inserts arranged in thereceiving pockets 12 and 12′ respectively also respectively overlap withone of the groups of cutting inserts which are arranged in the receivingpockets 11 and 11′ respectively. In a tangential view in the peripheraldirection in which the successive cutting inserts are shown in the sameplane, it is possible to see the profile 20 formed by that arrangement,as is illustrated in FIG. 4c. In order better to distinguish theindividual cutting inserts from each other, in that case the left,vertically arranged cutting insert and the right horizontal cuttinginsert are respectively identified by hatching. As will be seentherefrom the cutting inserts arranged in the pockets 11, 11′ cut withtheir secondary edges 5 which project in the radial direction somewhatfurther than the main cutting edges 4, 4′ of the horizontally arrangedcutting inserts 1 which cut the central part of a profile or cam 20. Asa result the milling cutting edges at the transition between thesecondary cutting edges 5 and the main cutting edges 4 come intoengagement with the edges of the profile 20, so that overall the resultproduced is a cam or disk profile with bevelled edges.

[0039]FIG. 5 shows in sub-FIGS. 5a, 5 b and 5 c various alternativefixing configurations for the cutting inserts 1 and FIG. 5d again showsin a development the precise arrangement of the cutting inserts 1,corresponding to the view in FIG. 4b. FIG. 5a shows a receiving pocketwhich, by virtue of faces 13 and 19 which are angled relative to eachother, defines a seat for a reversible cutting plate 1, while a reliefgroove 14 can be seen at the transition of the faces 13, 19. A rake faceof the cutting insert 1 bears against the face 13 and a secondary flankface 5 bears against the face 9. FIGS. 5b and c show an alternativeconfiguration in which there is only one contact face 13, whereininstead of a further contact face 19 it is possible to see a projection16 at the bottom of the plate seat, which engages into the depressionformed in the flank 3 by the opening 6, and thereby defines a clearlydefined plate seat. The projection 16 is of a trapezoidal cross-sectionwhich is precisely matched to the trapezoidal cross-section of theopenings 16 in the cutting bits 1. In plan view it also appearssubstantially in the form of a parallelogram with the same parallelogramangles as the cutting insert and its lateral contact faces which clearlyfix the cutting insert 1 in the axial direction with respect to the toolbody 10 extended parallel to the peripheral direction or the cuttingdirection.

[0040] It will be appreciated that a corresponding projection 16 couldadditionally be provided also on the other side of the fixing bore inorder to fix the cutting insert in the above-mentioned axial directionat two points which are remote from each other. It will be noted thatthis function is also performed in any case by the contact face 13 whichsupports the cutting insert 1 in the peripheral direction and thusagainst the cutting forces which act at the cutting edges.

[0041] It will be clear from FIG. 5d how the individual plates aredisplaced relative to each other and thereby overall define the profileillustrated in FIG. 4c.

[0042]FIGS. 6 and 7 show two embodiments of the present invention in a:substantially realistic perspective view. As can be easily appreciatedby means of comparison with FIG. 1, all faces, edges, openings and soforth defined in the description relating to FIG. 1 are also present inthe same manner in the embodiments shown in FIGS. 6 and 7. Only theproportions of the individual elements relative to each other aresomewhat different from the view in FIG. 1.

1. A cutting insert for cutting metal machining and for tangential and/or radial installation on a disk milling cutter, in particular for milling camshafts, comprising at least one cutting edge (4, 4′) formed by the intersection of a rake face (2) with a flank (3), characterised in that the cutting insert in plan view on to the flank (3) is in the shape of a parallelogram which is not right-angled, wherein the main cutting edge extends at an angle differing from 90° relative to the cutting direction and wherein the cutting direction is defined substantially by structures (7, 8) which are provided on the flank.
 2. A cutting insert as set forth in claim 1 characterised in that the angle between the main cutting edge (4, 4′) and the cutting direction is between 40 and 85°, in particular between 50 and 75° and preferably between 55 and 65°.
 3. A cutting insert as set forth in one of claims 1 and 2 characterised in that the main cutting edges (4, 4′) are each interrupted and comprise at least a first cutting edge portion (4) and a second cutting edge portion (4′).
 4. A cutting insert as set forth in claim 3 characterised in that the internal spacing between the cutting edge portions (4, 4′) of the main cutting edge is shorter than the length of a respective one of the preferably equal-length cutting edge portions (4, 4′).
 5. A cutting insert as set forth in claim 4 characterised in that the internal spacing between the cutting edge portions (4, 4′) is between 70 and 95%, preferably between 75 and 90%, of the length of the cutting edge portions (4, 4′).
 6. A cutting insert as set forth in one of claims 1 through 5 characterised in that the respective ends of the cutting edge portions (4, 4′) are angled, preferably through about 45°.
 7. A cutting insert as set forth in one of claims 1 through 6 characterised in that cutting edges (4, 4′) are respectively provided on rake faces (2) of the cutting insert, which rake faces face away from each other.
 8. A cutting insert as set forth in one of claims 1 through 7 characterised in that cutting edges are provided on the same side of a rake face (2), but with flanks which face away from each other.
 9. A cutting insert as set forth in one of claims 1 through 8 characterised in that there are provided secondary cutting edges (5) which adjoin the outer ends of the main cutting edges (4, 4′) or the angled end portions thereof and which extend substantially at a right angle to the main cutting edges (4, 4′).
 10. A cutting insert as set forth in one of claims 1 through 9 characterised in that the main cutting edges (4, 4′) are slightly curved or extend angled through a small angle relative to each other.
 11. A cutting insert as set forth in claim 10 characterised in that the radius of curvature of the cutting edges is greater than 300 mm and smaller than 2000 mm.
 12. A cutting insert as set forth in claim 10 or claim 11 characterised in that the mutually remote ends of the main cutting edges or main cutting edge portions (4, 4′) include with each other an angle which is greater than 1° and less than 10°.
 13. A milling cutter for cutting machining of a workpiece comprising a tool body (10) which is substantially cylindrical or in the form of a circular disk with a plurality of receiving pockets (11, 11′, 12, 12′) for cutting inserts (1) which are distributed along the periphery of the tool body (10) wherein at least a part of the receiving pockets (11, 11′, 12, 12′) is so arranged that the active cutting edges of the cutting inserts (1) received therein extend inclinedly in the peripheral direction relative to the axis of the tool body (10, characterised in that there are provided the receiving pockets for receiving cutting inserts as set forth in one of claims 1 through 12 and arranged in such a way that the active cutting edges of the cutting inserts (1) received therein extend inclined relative to the axis of the tool body (10) through at least between 10 and 40° and in such a way that structures on the flanks of the cutting inserts extend substantially in the cutting direction.
 14. A milling cutter as set forth in claim 13 characterised in that the angle of inclination of the cutting edges relative to the axis of the tool body is between 25 and 35°.
 15. A milling cutter as set forth in claim 13 or claim 14 characterised in that all active main cutting edges (4, 4′) are inclined with respect to the axis of the tool body (10).
 16. A milling cutter as set forth in claim 15 characterised in that the V main cutting edges are all inclined in the same direction with respect to the axis of the tool body (10).
 17. A milling cutter as set forth in one of claims 13 through 16 characterised in that the active secondary cutting edges (5) of tool inserts (1) are inclined in the peripheral direction with respect to the axis of the tool body (10).
 18. A milling cutter as set forth in claim 17 characterised in that the cutting inserts arranged at various corners between the periphery and the end faces of the tool body (10) have secondary cutting edges which are inclined in opposite directions.
 19. A milling cutter as set forth in one of claims 13 through 18 characterised in that a part of the cutting inserts is arranged in the corner regions between the peripheral surface and the two end faces of the substantially cylindrical tool body (10) and a further part is arranged on the periphery or the peripheral surface of the cylindrical tool body (10).
 20. A milling cutter as set forth in claim 19 characterised in that the cutting inserts are arranged on the tool-body (10) in four different groups characterised by their position, wherein the cutting inserts of a first and a second group are respectively arranged in the corner region between the peripheral surface and the two end faces of the cylindrical tool body while the other two groups are distributed displaced in the axial direction relative to each other along the periphery or peripheral surface of the cylindrical tool body (10).
 21. A milling cutter as set forth in claim 20 characterised in that the cutting inserts are arranged overlapping with their cutting edges (4, 4′, 5) in such a way that the one group of the cutting inserts (1) arranged on the peripheral surface of the tool body (10) is arranged relative to the other group of the cutting inserts (1) arranged on the peripheral surface, in such a way that a respective one of the main cutting edge portions (4, 4′) of the one group covers the interruption region (6) between the main cutting edge portions (4, 4′) of the respective other group and wherein the ends, which are respectively closest to the end faces of the tool body (10), of the main cutting edges of a respective one of the groups overlap with the secondary cutting edges (5) of the cutting inserts (1) arranged in the corner regions.
 22. A milling cutter as set forth in one of claims 13 through 21 characterised in that the tool body has seat surfaces (21) with a protruding projection (16) which upon receiving a cutting insert (1) engages into a suitable opening (6) therein.
 23. A milling cutter as set forth in claim 22 characterised in that the projection (16) and the opening (6) are so matched to each other that the projection (16) secures the cutting insert (1) in at least one direction to prevent displacement thereof with respect to the seat surface (21).
 24. A milling cutter as set forth in claim 23 characterised in that the seat surface (21) is arranged along the peripheral surface of the tool body (10), wherein the projection (16) is arranged in such a way that it fixes the cutting insert (1) in the axial direction of the substantially cylindrical tool body (10). 